Refining and bleaching fatty acid esters



the dry state.

United States Patent & Co., In ware New York, N. Y., assignor to E. F. Drew c., New York, N. Y., a corporation of Dela- No Drawing. Application February 24, 1951, Serial No. 212,678

6 Claims. (Cl. 260410.6)

The present invention as the neutral fatty acid and more particularly to substances.

It has been customary compositions for industrial esterify the constituents to is directed to fatty acids such esters of polyhydric alcohols a method for purifying such In many cases the bleachwhen the crude ester was The loss in the alkali requite substantial.

earthy material or the like. ing was ineffective especially of a relatively dark color.

It is also among the objects of the present invention to provi scale without the necessity for a double set of equipment for conducting the operation.

The present invention is based upon the use in the refining operation of hydrogen peroxide together with alkaline agents. The crude ester, which may be a glyceride ester of fatty acids or the polyglycol esters of such acids, is mixed with an alkaline compound in The alkaline compound is an alkali metal carbonate. The mixture is heated with agitation to a temperature of from 80 to'110 C. in the presence of a 30% aqueous solution of hydrogen peroxide. The amount of hydrogen peroxide used is about .5 to 2.5% by weight of the crude ester being treated. An excess of alkali metal carbonate is then added in amounts sufficient to neutralize all of the free fatty acid present in the crude ester and the mixture is agitated, the temperature being above room temperature but usually below the temperature of treatment with hydrogen peroxide. The mixture is then allowed to settle and the aqueous layer containing soaps of the fatty acids is drawn off from the bottom of the refining kettle. The refined ester is then dried and is ready for use.

The following is a specific example of the operation of the present invention.

Example 4,000 lbs. of the above crude ester are mixed with 2,705,722 Patented Apr. 5, 1955 to disperse the soda ash throughout the crude ester. There is then added 80 lbs. of a 30% aqueous hydrogen peroxide solution while continuing the agitation for several hours and heating the mixture to about C. This results i a combined bleaching and refining The soap solution is withdrawn from the bottom of the refining kettle, the refined ester is heated to about C. in the presence of a vacuum to remove traces of water and it is filtered through bleaching earth or activated carbon. This results in a removal of suspended matter and a deodorization of the refined ester, which has the following analysis.

fifa (as oleic) 0.15 Color (Lovibond Red 5%" Col) 10/ 1.2 Sap value 272 sh 0.0015 Acetyl value 13.0 IV 0.4 There are a number of advantages inherent in the details may made without departing from the principles herein set forth. or instance, other fatty esters than those specifically set forth herein may be treated by the present process. be obtained from animal or vegetable oils or from other For instance, if an ester has more or less color to be removed therefrom, correspondingly more or less hydrogen peroxide is used. The temperatures of the operation may be varied within the stated limits with good results, depending upon the character of the op eration being conducted.

These and other changes may be made in the details of the operation within the spirit of the invention, which is to be broadly construed and not to be limited exgeplt by the character of the claims appended hereto.

c arm:

1. A method of simultaneously alkali refining and bleaching crude substantially neutral and water insoluble fatty acid esters agitating said mixture, thereafter introducing from 0.5 to 2.5% by weight of said ester of a 30% aqueous hydrogen peroxide solution, heating said mixture from 80 C. to 110 C. While agitating the same to cause bleaching, allowing the mixture to settle into two layers and recovering the ester.

2. A method of simultaneously alkali refining and ester an amount of a dry alkali metal carbonate at least suflicient to neutralize all the free fatty acids contained therein, heating and agitating said mixture, thereafter introducing from 0.5

to 2.5% by weight of said ester of a 30% aqueous hyuble fatty acid esters of polyhydric alcohols taken from drogen peroxide solution, heating said mixture from the class conslsting of glycerol and polyglycols which 80 C. to 110 C. while agitating the same to cause comprises adding to said ester an amount of a subbleaching, allowing the mixture to settle into two laystantially dry sodium carbonate at least sufiicient to ers and recovering the ester, and then heating said 5 neutralize all the free fatty acids contained therein, ester above 100 C. in a vacuum to remove traces of heating to about 50 C. and agitating said mixture, water. thereafter introducing 2% by weight of said ester of a 3. A method of simultaneously alkali refining and 30% aqueous hydrogen peroxide solution, heating said bleaching crude substantially neutral and water insolmixture from 90 C. to 95 C. while agitating the same uble fatty acid esters of polyhydric alcohols taken from to cause bleaching, allowing the mixture to settle into the class consisting of glycerol and polyglycols which two layers and recovering the ester. comprises adding to said ester an amount of a dry al- 6. A method of simultaneously alkali refining and kali metal carbonate at least sufficient to neutralize all bleaching crude substantially neutral and water insolthe free fatty acids contained therein, heating to about uble fatty acid esters of polyhydric alcohols taken from 50 C. and agitating said mixture, thereafter introducthe class consisting of glycerol and polyglycols which ing from 0.5 to 2.5% by weight of said ester of a comprises adding to said ester an amount of a dry soaqueous hydrogen peroxide solution, heating said mixdium carbonate at least suflicient to neutralize all the ture from C. to 110 C. while agitating the same free fatty acids contained therein, heating to about to cause bleaching, allowing the mixture to settle into 50 C. and agitating said mixture, thereafter introductwo layers and recovering the ester. 20 ing 2% by weight of said ester of a 30% aqueous hy- 4. A method of simultaneously alkali refining and drogen peroxide solution, heating said mixture from bleaching crude substantially neutral and water insol- C. to C. while agitating the same for several uble fatty acid esters of polyhydric alcohols taken from hours to cause bleaching, allowing the mixture to set- 'the class consisting of glycerol and polyglycols which tie into two layers and recovering the ester, and then comprises adding tosaid ester an amount of a dry so 25 heating said ester from C. to C. in a vacudium carbonate at least sufiicient to neutralize all the um to remove traces of water. free fatty acids contalned therein, heating to about 50 and agitatirgg7 szlaaid mixglregf therdeafter llll'Odilcilllyg References Cited in the file of this patent rom 0.5 to 2. o y weig t o sai ester 0 a 30 0 aqueous hydrogen peroxide solution, heating said mix- 30 UNlTED STATES PATENTS ture from 90 C. to 95 C. while agitating the same to 2,113,433 Reichert et al. Apr. 5, 1938 cause bleaching, allowing the mixture to settle into two 2,121,545 Kokatnur et al. June 21, 1938 layers and recovering the ester. 2,221,559 Scheller Nov. 12, 1940 v5. A method of simultaneously alkali refining and 2,524,056 Jespersen Oct. 3, 1950 bleaching crude substantially neutral and water insol- 35 

1. A METHOD OF SIMULTANEOUSLY ALKALI REFINING AND BLEACHING CRUDE SUBSTANTIALLY NEUTRAL AND WATER INSOLUBLE FATTY ACID ESTERS OF POLYHYDRIC ALCOHOLS TAKEN FROM THE CLASS CONSISTING OF GLYCEROL AND POLYGLYCOLS WHICH COMPRISES ADDING TO SAID ESTER AN AMOUNT OF A DRY ALKALI METAL CARBONATE AT LEAST SUFFICIENT TO NEUTRALIZE ALL THE FREE FATTY ACIDS CONTAINED THEREIN, HEATING AND AGITATING SAID MIXTURE, THEREAFTER INTRODUCING FROM 0.5 TO 2.5% BY WEIGHT OF SAID ESTER OF A 30% AQUEOUS HYDROGEN PEROXIDE SOLUTION, HEATING SAID MIXTURE FROM 80*C. TO 110*C. WHILE AGITATING THE SAME TO CAUSE BLEACHING, ALLOWING THE MIXTURE TO SETTLE INTO TWO LAYERS AND RECOVERING THE ESTER. 